The invention generally relates to window blinds for use in automobiles.
A roll-up window blind for automobile rear window panes is know from DE-A-198 35 257. With this blind, the blind material is clamped and supported exclusively by means of two clamping levers. The levers are essentially rigid and resistant to bending. The levers are supported on pivots beside the winding shaft, the axis of which lies at a right angle to the axis of the winding shaft. The winding shaft is prestressed by a spring motor in the wind-up direction of the blind material, while the levers are swung upward with the aid of an electric motor. In the reeled-in position, the levers lie parallel to the winding shaft, while with the rolled-out blind they run likewise at a right angle to the winding shaft.
The clamping levers certainly are relatively stiff and also stiffly supported, but not so stiffly that they cannot start vibrating when normal jolting of the vehicle occurs. In order to avoid these vibrations, which would be troublesome especially in the reeling-out process and could lead to the pull rod striking on the rear window pane, the clamping levers are slanted in such manner that in the area of the end of the path range with the reeled-out blind the clamping levers press the pull rod against the pane with the help of guide skids. In the lower range, the levers and the pull rod move freely, which is forced by reason of the slant of the rear windowpane and the distance which the winding shaft must maintain from the curved rear windowpane.
In order to avoid damage to the heating wires on the inside of the rear windowpane, the pull rod is equipped with guide elements in the form of small rollers or small wheels. These small wheels during the reeling-in of the blind are pushed back behind the contour of the pull rod, so that when the blind is reeled-in, the outlet slot is nearly completely closed.
With the known blind, the guide rollers in the reeled-out state are rigidly supported. The pressure force applied by the guide rollers is produced by the particular installation geometry. Because of installation tolerances, non-inappreciable fluctuations can occur with respect to the pressing-on force.
Accordingly, in view of the foregoing, a general object of the present invention is to provide a roll-up window blind particularly for rear windowpanes of automobiles in which the pressing-on force applied by the guide elements is less strongly dependent on the installation tolerances than with known conventional blinds.
In the new roll-up window blind, means are provided which impart to the guide elements a yieldingness or movability in a direction perpendicular to the windowpane of the vehicle. In this manner, the pressing-on force with which the guide rollers lie against the pane can be kept relatively constant particularly, when, because of the installation tolerances, the position of the winding shaft deviates with the respect to the theoretical desired extent and/or when the plane in which the actuating elements swing encloses, with the rear windowpane, an angle different from the theoretical desired angle.
The guide elements can be constructed optionally as rollers or as slide skids.
The mechanism which can impart to the guide elements the desired yieldingness or movability in a direction perpendicular to the pane can be constructed in different ways and in different locations. One possibility lies in yieldingly or movably supporting the guide elements on the pull rod. For this purpose, a small housing in which there is movably accommodated the support for the guide element is expediently provided, for example in the form of a pusher, which is slidable approximately perpendicular with respect to the plane that is defined by the tensioned blind material.
Another possibility for achieving the desired yieldingness or movability comprises providing the bearing by which the particular clamping lever is borne in fixed position with a corresponding shape. Thus, a pivot with a collar that leads through a bore that is surrounded by a bearing surface or shoulder can be used as the bearing. The pivot can optionally be made so as to be fastened to the body or can be provided on the actuating element while the bore is present either in the clamping lever or in a frame which also bears or supports the winding shaft. With the aid of a preferably disk-form spring, a plate spring or shaft spring, for example, the contact surface is pressed against the collar of the pivot, a preferred positioning is hereby achieved. By reason of a corresponding dimensioning of the diameter of the pivot to the bore, a certain tilting possibility is produced, whereby the actuating element can be swung not only about the axis of the pivot, but also limitedly in a plane which contains the axis of the pivot.
Finally, as a third possibility, it is also conceivable to endow the actuating element itself with a certain flexibility, for example in the form of a band spring instead of a tube, which as compared with the band spring is very resistant to bending and would lead to undesirably great forces when the winding shaft is too close to the rear windowpane, or to forces that are much too small, should the distance be too great.
Depending on the embodiment, the winding shaft can be accommodated in a housing if the built-up solution is preferred, or it can be borne on a frame if the winding shaft, for example, is arranged underneath the hat rack or rear shelf through which the blind material and actuating elements emerge.
For driving the roll-up blind, the combination of a spring drive and an electric drive can be used. In such a situation, the spring drive functions as slave while the position of the pull rod is defined by the self-inhibiting electric motor. The electric motor can drive the winding shaft or the actuating elements, in which case the spring drive is coupled with the respective other component.
As actuating elements, the possibilities include simple levers or also toggle levers that are made up of two toggle lever pieces. In one case, a sliding movement is needed between the actuating element and the pull rod, while in the other case an additional hinge provides for instability, or also can be used as a means to generate the yieldingness or movability of the guide elements.
These and other features and advantages of the invention will be more readily apparent upon reading the following description of preferred exemplary embodiments of the invention and upon reference to the drawings wherein: